Darth Maul vs Kit Fisto

Canonically, Kit Fisto's only major feat is coming very close to killing Grievous within his own lair, which is fairly impressive except for the fact that Grievous is not force-sensitive. Other than that, we have only his performance at Geonosis and his swift death at the hands of the Spinning Sith AKA Darth Sidious.

Darth Maul slew Qui-Gon and held off Obi-Wan before getting bisected and falling into the pit, although he survived. He then founded a crime syndicate, took over Mandalore, and successfully escaped after being captured by Sidious, including holding his own against Sidious in one-on-one combat for short periods of time. He's fought numerous Mandalorian warriors, including one wielding the Darksaber. He's fought Ahsoka Tano numerous times (before and after Fulcrum), as well as Kanan Jarrus. He held off Obi-Wan in a fight as well, although he ultimately met his end in the Dune Sea.

Maul's feats exceed Kit Fisto's any day. Kit Fisto didn't last 5 seconds with Sidious despite being backed up by multiple Jedi Council members. Maul has fought toe-to-toe with Sidious on his own and survived, if only for short periods of time.